U.S. patent application number 12/799683 was filed with the patent office on 2010-11-25 for power feeding system, power feeder, power-receiving equipment, and positioning control method.
This patent application is currently assigned to Sony Corporation. Invention is credited to Dai Sato, Naho Suzuki, Kazuhiro Uchida.
Application Number | 20100295378 12/799683 |
Document ID | / |
Family ID | 43104264 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100295378 |
Kind Code |
A1 |
Suzuki; Naho ; et
al. |
November 25, 2010 |
Power feeding system, power feeder, power-receiving equipment, and
positioning control method
Abstract
A power feeding system includes: a power feeder including a
mount, a primary coil, a moving means, a query output means
outputting a query, a receiving means receiving notification
information, a primary coil direct-current driving control means
controlling the primary coil to be driven with a direct current, a
query control means allowing the query output means to output a
query, and a primary coil alternating-current driving control means
controlling the primary coil to be driven with an alternating
current; and a power-receiving equipment including a secondary
coil, a sensing means disposed at a position where the sensing
means can sense the query, a secondary coil direct-current driving
control means controlling the secondary coil to be driven with a
direct current, a notification information output means, and a
secondary coil alternating-current driving control means
controlling the secondary coil so that electromotive force induced
by the primary coil is exerted.
Inventors: |
Suzuki; Naho; (Tokyo,
JP) ; Uchida; Kazuhiro; (Kanagawa, JP) ; Sato;
Dai; (Saitama, JP) |
Correspondence
Address: |
LERNER, DAVID, LITTENBERG,;KRUMHOLZ & MENTLIK
600 SOUTH AVENUE WEST
WESTFIELD
NJ
07090
US
|
Assignee: |
Sony Corporation
Tokyo
JP
|
Family ID: |
43104264 |
Appl. No.: |
12/799683 |
Filed: |
April 29, 2010 |
Current U.S.
Class: |
307/104 |
Current CPC
Class: |
H02J 7/025 20130101;
H02J 50/10 20160201; H02J 7/0042 20130101; H02J 50/90 20160201 |
Class at
Publication: |
307/104 |
International
Class: |
H02J 17/00 20060101
H02J017/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 21, 2009 |
JP |
P2009-123178 |
Claims
1. A power feeding system comprising: a power feeder; and
power-receiving equipment that receives power fed from the power
feeder, wherein the power feeder includes a mount on which the
power-receiving equipment is placed, a primary coil, a moving means
that makes the primary coil movable, a query output means that is
disposed so that the positional relationship to the movable primary
coil remains unchanged, and outputs a query to outside using a
predetermined medium, a receiving means that when the query is
sensed by the power-receiving equipment, receives notification
information outputted from the power-receiving equipment, a primary
coil direct-current driving control means that when the
power-receiving equipment is placed on the mount, as long as the
primary coil is made movable by the moving means, controls the
primary coil so that the primary coil is driven with a direct
current over a certain time length, a query control means that
after driving the primary coil with a direct current is begun,
allows the query output means to output a query, and a primary coil
alternating-current driving control means that after the
notification information outputted from the power-receiving
equipment in response to the query outputted by the query control
means is received by the receiving means, controls the primary coil
so that the primary coil can be driven with an alternating current,
and the power-receiving equipment includes a secondary coil
incorporated to be stationary in the power-receiving equipment, a
sensing means that is disposed at a position in the power-receiving
equipment at which when the positional relationship between the
primary coil and secondary coil falls within a proper range, the
sensing means can sense the query, a secondary coil direct-current
driving control means that when the power-receiving equipment is
placed on the power feeder, controls the secondary coil so that the
secondary coil is driven with a direct current in order to exert
attraction with respect to the primary coil which is driven with a
direct current, a notification information output means that after
the driving with a direct current is begun by the secondary coil
direct-current driving control means, when the query is sensed by
the sensing means, outputs the notification information, and a
secondary coil alternating-current driving control means that after
the driving with a direct current is begun by the secondary coil
direct-current driving control means, when the query is sensed by
the sensing means, controls the secondary coil so that
electromotive force induced by the primary coil which is driven
with an alternating current is exerted.
2. The power feeding system according to claim 1, wherein in the
power feeder, when the notification information responding to the
query outputted by the query control means is not received by the
receiving means, the primary coil direct-current driving control
means re-executes the driving of the primary coil with a direct
current over the certain time length; and after the re-executed
driving of the primary coil with a direct current is begun, the
query control means allows the query output means to output a query
again.
3. The power feeding system according to claim 1 or 2, wherein when
the query is outputted by the query control means, the primary coil
direct-current driving control means ceases the driving of the
primary coil with a direct current.
4. The power feeding system according to any of claims 1 to 3,
wherein the moving means includes a movable member having the
primary coil, and a movable member bearing region located below the
movable member; and friction between the movable member and movable
member bearing region is reduced to such an extent that the primary
coil can be moved with the attraction exerted between the primary
coil and secondary coil.
5. The power feeding system according to any of claims 1 to 4,
wherein the mount includes an electromagnet, further comprising: an
electromagnet driving means that when the primary coil is driven
with a direct current by the primary coil direct-current driving
control means, drives the electromagnet so that repulsion is
exerted with respect to the primary coil.
6. The power feeding system according to any of claims 1 to 4,
wherein the mount is structured to have a plurality of spherical
pieces arranged in planar directions.
7. The power feeding system according to any claims 1 to 6, wherein
the query output means outputs a query using light as the medium;
and the sensing means senses the light.
8. The power feeding system according to any of claims 1 to 7,
wherein the power-receiving equipment includes a charging means
that charges the secondary battery by utilizing the induced
electromotive force exerted in the secondary coil.
9. A power feeding system comprising: a power feeder; and
power-receiving equipment that receives power fed from the power
feeder, wherein the power feeder includes a mount on which the
power-receiving equipment is placed, a primary coil, a moving means
that makes the primary coil movable, a sensing means disposed so
that the positional relationship to the movable primary coil
remains unchanged, and located at a position at which when the
positional relationship between the primary coil and a secondary
coil incorporated in the power-receiving equipment falls within a
proper range, the sensing means can sense a query outputted from
the power-receiving equipment, a primary coil direct-current
driving control means that when the power-receiving equipment is
placed on the mount, as long as the primary coil is made movable by
the moving means, controls the primary coil so that the primary
coil is driver with a direct current over a certain time length,
and a primary coil alternating-current driving control means that
after driving the primary coil with a direct current is begun, when
the query is sensed by the sensing means, controls the primary coil
so that the primary coil can be driven with an alternating current,
and the power-receiving equipment includes a secondary coil
incorporated to be stationary in the power-receiving equipment, a
query output means that outputs the query to outside using a
predetermined medium so that whether the positional relationship
between the primary coil and secondary coil falls within the proper
range can be decided, a secondary coil direct-current driving
control means that when the power-receiving equipment is placed on
the power feeder, controls the secondary coil so that the secondary
coil is driven with a direct current over the certain time length
in order to exert attraction with respect to the primary coil which
is driven with a direct current, a query control means that after
the secondary coil is driven with a direct current by the secondary
coil direct-current driving control means, allows the query output
means to output the query, and a secondary coil alternating-current
driving control means that after the secondary coil is driven with
a direct current by the secondary coil direct-current driving
control means, controls the secondary coil so that electromotive
force induced by the primary coil which is driven with an
alternating current is exerted.
10. The power feeding system according to claim 9, further
comprising a pulse application means that is incorporated in the
power feeder, and that when the query is sensed by the sensing
means, applies a pulse to the primary coil, and a pulse sensing
means that is incorporated in the power-receiving equipment, and
that senses a pulsating voltage induced by the secondary coil
responsively to the application of the pulse to the primary coil by
the pulse application means, wherein when the pulse is sensed by
the pulse sensing means, the secondary coil alternating-current
driving control means controls the secondary coil so that the
electromotive force induced by the primary coil which is driven
with an alternating current is exerted.
11. A power feeder comprising: a mount on which power-receiving
equipment is placed; a primary coil; a moving means that makes the
primary coil movable; a query output means that is disposed so that
the positional relationship to the movable primary coil remains
unchanged, and outputs a query to outside using a predetermined
medium; a receiving means that assuming that the positional
relationship between the primary coil and a secondary coil
incorporated to be stationary in the power-receiving equipment
falls within a proper range, when the query is sensed by the
power-receiving equipment, receives notification information
outputted from the power-receiving equipment; a primary coil
direct-current driving control means that when the power-receiving
equipment is placed on the mount, as long as the primary coil is
made movable by the moving means, controls the primary coil so that
the primary coil is driven with a direct current over a certain
time length in order to exert attraction with respect to the
secondary coil which is driven with a direct current in the
power-receiving equipment; a query control means that after driving
the primary coil with a direct current is begun, allows the query
output means to output the query; and a primary coil
alternating-current driving control means that after the
notification information outputted from the power-receiving
equipment in response to the query outputted by the query control
means is received by the receiving means, controls the primary coil
so that the primary coil can be driven with an alternating
current.
12. Power-receiving equipment comprising: a secondary coil
incorporated to be stationary in the power-receiving equipment; a
sensing means located at a position at which when the positional
relationship between a primary coil incorporated to be movable in a
power feeder and the secondary coil falls within a proper range,
the sensing means can sense a query outputted from the power
feeder; a secondary coil direct-current driving control means that
when the power-receiving equipment is placed on the power feeder,
controls the secondary coil so that the secondary coil is driven
with a direct current in order to exert attraction with respect to
the primary coil which is driven with a direct current in the power
feeder; a notification information output means that after the
driving with a direct current is begun by the secondary coil
direct-current driving control means, when the query is sensed by
the sensing means, outputs notification information; and a
secondary coil alternating-current driving control means that after
the driving with a direct current is begun by the secondary coil
direct-current driving control means, when the query is sensed by
the sensing means, controls the secondary coil so that
electromotive force induced by the primary coil which is driven
with an alternating current is exerted.
13. A power feeder comprising: a mount on which power-receiving
equipment is placed; a primary coil; a moving means that makes the
primary coil movable; a sensing means disposed so that the
positional relationship to the movable primary coil remains
unchanged, and located at a position at which when the positional
relationship between the primary coil and a secondary coil
incorporated to be stationary in the power-receiving equipment
falls within a proper range, the sensing means can sense a query
outputted from the power-receiving equipment; a primary coil
direct-current driving control means that when the power-receiving
equipment is placed on the mount, as long as the primary coil is
made movable by the moving means, controls the primary coil so that
the primary coil is driven with a direct current over a certain
time length in order to exert attraction with respect to the
secondary coil which is driven with a direct current in the
power-receiving equipment; and a primary coil alternating-current
driving control means that after driving the primary coil with a
direct current is begun, when the query is sensed by the sensing
means, controls the primary coil so that the primary coil can be
driven with an alternating current.
14. Power-receiving equipment comprising: a secondary coil
incorporated to be stationary in the power-receiving equipment; a
query output means that outputs a query to outside using a
predetermined medium so that whether the positional relationship
between a primary coil incorporated in a power feeder and the
secondary coil falls within a proper range can be decided; a
secondary coil direct-current driving control means that when the
power-receiving equipment is placed on the power feeder, controls
the secondary coil so that the secondary coil is driven with a
direct current over a certain time length in order to exert
attraction with respect to the primary coil which is driven with a
direct current; a query control means that after the secondary coil
is driven with a direct current by the secondary coil
direct-current driving control means, controls the secondary coil
so that electromotive force induced by the primary coil which is
driven with a direct current is exerted; and a secondary coil
alternating-current driving control means that after the secondary
coil is driven with a direct current by the secondary coil
direct-current driving control means, controls the secondary coil
so that electromotive force induced by the primary coil which is
driven with an alternating current is exerted.
15. A positioning control method to be implemented in a power
feeding system including a power feeder and power-receiving
equipment that receives power fed from the power feeder, the method
comprising the steps of: when a query is sensed by the
power-receiving equipment, allowing the power feeder to receive
notification information outputted from the power-receiving
equipment; when the power-receiving equipment is placed on the
power feeder, as long as the primary coil is made movable by a
moving unit which makes the primary coil movable, allowing the
power feeder to control a primary coil so that the primary coil is
driven with a direct current over a certain time length; after
driving the primary coil with a direct current is begun, allowing a
query output unit, which is disposed in the power feeder so that
the positional relationship to the primary coil which is made
movable by the moving unit remains unchanged, and outputs a query
to outside using a predetermined medium, to output the query; after
the notification information outputted from the power-receiving
equipment in response to the query outputted at the query control
step is received at the receiving step, allowing the power feeder
to control the primary coil so that the primary coil can be driven
with an alternating current; when the power-receiving equipment is
placed on the power feeder, allowing the power-receiving equipment
to control a secondary coil so that the secondary coil incorporated
to be stationary in the power-receiving equipment is driven with a
direct current in order to exert attraction with respect to the
primary coil which is driven with a direct current; after driving
with a direct current is begun at the secondary coil direct-current
driving control step, when the query is sensed by a sensing unit
that is located at a position at which when the positional
relationship between the primary coil and the secondary coil
incorporated to be stationary in the power-receiving equipment
falls within a proper range, the sensing unit can sense the query,
allowing the power-receiving equipment to output the notification
information; and after the driving with a direct current is begun
at the secondary coil direct-current driving control step, when the
query is sensed by the sensing unit, allowing the power-receiving
equipment to control the secondary coil so that electromagnetic
force induced by the primary coil which is driven with a direct
current is exerted.
16. A positioning control method to be implemented in a power
feeder, the method comprising the steps of: when the positional
relationship between the primary coil and a secondary coil
incorporated to be stationary in the power feeder falls within a
proper range, if a query outputted from a query output unit, which
is disposed so that the positional relationship to a primary coil
to be made movable by a moving unit that makes the primary coil
movable remains unchanged, to outside using a predetermined medium
is sensed by the power-receiving equipment, receiving notification
information outputted from power-receiving equipment; when the
power-receiving equipment is placed on a mount, as long as the
primary coil is made movable by the moving unit, controlling the
primary coil so that the primary coil is driven with a direct
current over a certain time length in order to exert attraction
with respect to the secondary coil which is driven with a direct
current in the power-receiving equipment; after driving the primary
coil is begun, allowing the query output unit to output a query;
and after the notification information outputted from the
power-receiving equipment in response to the query outputted at the
query control step is received at the receiving step, controlling
the primary coil so that the primary coil can be driven with an
alternating current.
17. A positioning control method to be implemented in
power-receiving equipment, the method comprising the steps of: when
the power-receiving equipment is placed on a power feeder,
controlling a secondary coil, which is incorporated to be
stationary in the power-receiving equipment, so that the secondary
coil is driven with a direct current in order to exert attraction
with respect to a movable primary coil which is driven with a
direct current in the power feeder; after driving with a direct
current is begun at the secondary coil direct-current driving
control step, if a query is sensed by a sensing unit that is
located at a position in the power-receiving equipment at which
when the positional relationship between the primary coil of the
power feeder and the secondary coil of the power-receiving
equipment falls within a proper range, the sensing unit can sense
the query outputted from the power feeder, outputting notification
information; and after the driving with a direct current is begun
at the secondary coil direct-current driving control step, when the
query is sensed by the sensing unit, controlling the secondary coil
so that electromotive force induced by the primary coil which is
driven with an alternating current is exerted.
18. A positioning control method to be implemented in a power
feeding system including a power feeder and power-receiving
equipment that receives power fed from the power feeder, the method
comprising the steps of: when the power-receiving equipment is
placed on a mount of the power feeder, allowing the power feeder to
control a primary coil, which is made movable by a moving unit that
makes the primary coil movable, so that the primary coil is driven
with a direct current over a certain time length; after driving the
primary coil with a direct current is begun, when a query is sensed
by a sensing unit that is disposed so that the positional
relationship to the movable primary coil remains unchanged and that
is located at a position at which when the positional relationship
between the primary coil and a secondary coil of the
power-receiving equipment falls within a proper range, the sensing
unit can sense the query sent from the power-receiving equipment,
allowing the power feeder to control the primary coil so that the
primary coil can be driven with an alternating current; when the
power-receiving equipment is placed on the power feeder, allowing
the power-receiving equipment to control the secondary coil, which
is incorporated to be stationary in the power-receiving equipment,
so that the secondary coil is driven with a direct current over the
certain time length in order to exert attraction with respect to
the primary coil which is driven with a direct current; after the
secondary coil is driven with a direct current at the secondary
coil direct-current driving control step, allowing a query output
unit, which is included in the power-receiving equipment and
outputs a query to outside using a predetermined medium, to output
the query so that whether the positional relationship between the
primary coil and secondary coil falls within a proper range can be
decided; and after the secondary coil is driven with a direct
current at the secondary coil direct-current driving control step,
allowing the power-receiving equipment to control the secondary
coil so that electromotive force induced by the primary coil which
is driven with an alternating current is exerted.
19. A positioning control method to be implemented in a power
feeder, the method comprising the steps of: when power-receiving
equipment is placed on a mount of the power feeder, as long as a
primary coil is made movable by a moving unit that makes the
primary coil movable, controlling the primary coil so that the
primary coil is driven with a direct current over a certain time
length in order to exert attraction with respect to a secondary
coil which is driven with a direct current in the power-receiving
equipment; and after driving the primary coil with a direct current
is begun, when a query is sensed by a sensing unit that is disposed
so that the positional relationship to the primary coil which is
made movable by the moving unit remains unchanged and that is
located at a position at which when the positional relationship
between the primary coil and the secondary coil incorporated to be
stationary in the power-receiving equipment falls within a proper
range, the sensing unit can sense the query, controlling the
primary coil so that the primary coil can be driven with an
alternating current.
20. A positioning control method to be implemented in
power-receiving equipment, the method comprising the steps of: when
the power-receiving equipment is placed on a power feeder,
controlling a secondary coil, which is incorporated to be
stationary in the power-receiving equipment, so that the secondary
coil is driven with a direct current over a certain time length in
order to exert attraction with respect to a movable primary coil
which is driven with a direct current; after the secondary coil is
driven with a direct current at the secondary coil direct-current
driving control step, allowing a query output unit, which outputs a
query to outside using a predetermined medium, to output the query
so that whether the positional relationship between the primary
coil and secondary coil falls within a proper range can be decided;
and after the secondary coil is driven with a direct current at the
secondary coil direct-current driving control step, controlling the
secondary coil so that electromotive force induced by the primary
coil which is driven with an alternating current is exerted.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from Japanese Patent
Application No. JP 2009-123178 filed in the Japanese Patent Office
on May 21, 2009, the entire content of which is incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a power feeding system that
performs non-contact power feeding which is represented by, for
example, non-contact charging. In addition, the present invention
relates to a positioning control method that is implemented in the
power feeding system and is concerned with a charging position for
a power feeder and power-receiving equipment.
[0004] 2. Description of the Related Art
[0005] A technology for charging electronic equipment (secondary
battery) in a non-contact manner has been known in the past.
[0006] For the non-contact charging, for example, a primary coil is
incorporated in a charger and a secondary coil is incorporated in
electronic equipment. For charging, the electronic equipment is
placed at a given specified position in the charger and the primary
coil is driven. Accordingly, induced electromotive force is exerted
between the primary coil and secondary coil. In the electronic
equipment, the induced electromotive force is used to charge a
secondary battery.
[0007] In a system in which non-contact charging is performed as
mentioned above, when electronic equipment is placed on a charger,
the electronic equipment has to be positioned so that a state in
which the distance between an internal primary coil and secondary
coil falls below a certain value will be retained. In a state in
which the distance between the primary coil and secondary coil is
equal to or larger than the certain value, the coupling between the
primary coil and secondary coil becomes insufficient. Eventually,
appropriate transmission of power fails.
[0008] For the positioning, a constitution in which after a
magnetic pole member of a stand is opposed to a magnetic pole
member of electronic equipment, when the main body of the
electronic equipment is abutted on the external surface of the
stand, the electronic equipment is reliably mounted owing to
attraction is described in JP-A-4-197040 (patent document 1).
[0009] As described in JP-A-63-59734 (patent document 2), a method
of engaging electronic equipment with a charger by forming a
physical shape such as a concave part in one of them is widely
known.
[0010] JP-A-6-153411 (patent document 3) discloses a constitution
in which: a rechargeable battery is disposed together with a load
in a moving unit in such a manner that the battery can be moved;
and when the moving unit is located at a home position, a charging
power supply performs non-contact charging on the rechargeable
battery.
[0011] JP-A-2008-301553 (patent document 4) discloses a
constitution in which: a mirror-finished surface bearing a
permissible range mark indicating the center of a primary
transmission coil is formed at a position equivalent to the
position of the primary transmission coil incorporated in a mount
of a cradle; and a center position mark is inscribed at a position
equivalent to the position of the center of a secondary
transmission coil incorporated in a portable cellular phone that is
equipment to be charged. In the constitution, while the center
position mark of the portable cellular phone is reflected on the
permissible range mark of the mount, the center position of the
secondary transmission coil is matched with the center position of
the primary transmission coil and the portable cellular phone is
placed on the mount. Thus, the portable cellular phone is readily
located at the accurate position on the mount.
SUMMARY OF THE INVENTION
[0012] In the constitution described in the patent document 1,
attraction existent between magnetic pole members formed with, for
example, silicon steel plates is utilized. According to the patent
document 1, the attraction is exerted between the magnetic pole
members, and a charging current is induced at the same time. This
means that coils are driven with an alternating current in order to
exert the attraction between the magnetic pole members.
[0013] However, in reality, attraction is not exerted between the
magnetic pole members by driving the coils with an alternating
current. Therefore, the constitution described in the patent
document 1 is thought to be quite unfeasible in practice.
[0014] For example, according to the patent document 2, positioning
can be readily achieved by forming physical shapes. However, in the
constitution described in the patent document 2, a charger and
electronic equipment have to have physical engagement facilitating
shapes. Therefore, pieces of electronic equipment capable of using
the charger are limited to a small number of specific models. It is
hard to ensure high versatility and universality.
[0015] When an attempt is made to apply the constitution described
in the patent document 3 to a typical charging system, a moving
unit realized with a considerably complex mechanical facility
becomes necessary. This is disadvantageous in terms of, for
example, freedom in designing, cost, and a compact and lightweight
design.
[0016] According to the patent document 4, the number of compatible
models of equipment to be charged increases, and a universal
environment is established. However, this method depends on user's
visual inspection. Therefore, if a user carelessly places equipment
to be charged, the position of the equipment is deviated from a
proper position. If a permissible range is narrowed for some
reasons, it is hard for the user to accurately position the
equipment to be charged through visual inspection. The user may
find it a bother and may think it is hard to use the charger.
[0017] Thus, there is a need for a power feeding system that
exhibits high universality and ensures appropriate positioning
without bothering a user.
[0018] According to an embodiment of the present invention, there
is provided a power feeding system including a power feeder and
power-receiving equipment that receives power fed from the power
feeder. The power feeder includes: a mount on which the
power-receiving equipment is placed; a primary coil; a moving means
for making the primary coil movable; a query output means that is
disposed so that the positional relationship to the movable primary
coil remains unchanged, and that outputs a query to outside using a
predetermined medium; a receiving means that when the query is
sensed by the power-receiving equipment, receives notification
information outputted from the power-receiving equipment; a primary
coil direct-current driving control means that when the
power-receiving equipment is placed on the mount, as long as the
primary coil is made movable by the movable means, controls the
primary coil so that the primary coil is driven by a direct current
over a certain time length; a query control means that after
driving the primary coil with a direct current is begun, allows the
query output means to output a query; a primary coil
alternating-current driving control means that after the
notification information outputted from the power-receiving
equipment in response to the query is received by the receiving
means, controls the primary coil so that the primary coil can be
driven with an alternating current. The power-receiving equipment
includes: a secondary coil incorporated to be stationary in the
power-receiving equipment; a sensing means that when the positional
relationship between the primary coil and secondary coil falls
within a proper range, is disposed at a position in the
power-receiving equipment at which the sensing means can sense the
query; a secondary coil direct-current driving control means that
when the power-receiving equipment is placed on the power feeder,
controls the secondary coil so that the secondary coil is driven
with a direct current in order to exert attraction with respect to
the primary coil which is driven with a direct current; a
notification information output means that after the driving with a
direct current is begun by the secondary coil direct-current
driving control means, when the query is sensed by the sensing
means, outputs the notification information; and a secondary coil
alternating-current driving control means that after the driving
with a direct current is begun by the secondary coil direct-current
driving control means, when the query is sensed by the sensing
means, controls the secondary coil so that electromotive force
induced by the primary coil which is driven with an alternating
current is exerted.
[0019] Further, according to another embodiment of the present
invention, there is provided a power feeding system including a
power feeder and power-receiving equipment that receives power fed
from the power feeder. The power feeder includes: a mount on which
the power-receiving equipment is placed; a primary coil; a moving
means that makes the primary coil movable; a sensing means that is
disposed so that the positional relationship to the movable primary
coil remains unchanged, and that is located at a position at which
when the positional relationship between the primary coil and a
secondary coil incorporated in the power-receiving equipment falls
within a proper range, the sensing means can sense a query
outputted from the power-receiving equipment; a primary coil
direct-current driving control means that when the power-receiving
equipment is placed on the mount, as long as the primary coil is
made movable by the moving means, controls the primary coil so that
the primary coil is driver with a direct current over a certain
time length; and a primary coil alternating-current driving control
means that after driving the primary coil with a direct current is
begun, if the query is sensed by the sensing means, controls the
primary coil so that the primary coil can be driven with an
alternating current. The power-receiving equipment includes: a
secondary coil incorporated to be stationary in the power-receiving
equipment; a query output means that outputs a query to outside
using a predetermined medium so that whether the positional
relationship between the primary coil and secondary coil falls
within the proper range is decided; a secondary coil direct-current
driving control means that when the power-receiving equipment is
placed on the power feeder, controls the secondary coil so that the
secondary coil is driven with a direct current over a certain time
in order to exert attraction with respect to the primary coil which
is driven with a direct current; a query control means that after
the secondary coil is driven with a direct current by the secondary
coil direct-current driving control means, allows the query output
means to output a query; and a secondary coil alternating-current
driving control means that after the secondary coil is driven with
a direct current by the secondary coil direct-current driving
control means, controls the secondary coil so that electromotive
force induced by the primary coil which is driven with an
alternating current is exerted.
[0020] Further, according to still another embodiment of the
present invention, there is provided a power feeder including: a
mount on which power-receiving equipment is placed; a primary coil;
a moving means for making the primary coil movable; a query output
means that is disposed so that the positional relationship to the
movable primary coil remains unchanged and that outputs a query to
outside using a predetermined medium; a receiving means that when
the positional relationship between the primary coil and a
secondary coil incorporated to be stationary in the power-receiving
equipment falls within a proper range, if the query is sensed by
the power-receiving equipment, receives notification information
outputted from the power-receiving equipment; a primary coil
direct-current driving control means that when the power-receiving
equipment is placed on the mount, as long as the primary coil is
made movable by the moving means, controls the primary coil so that
the primary coil is driven with a direct current in order to exert
attraction with respect to the secondary coil driven with a direct
current in the power-receiving equipment; a query control means
that after driving the primary coil with a direct current is begun,
allows the query output means to output a query; and a primary coil
alternating-current driving control means that after the
notification information outputted from the power-receiving
equipment in response to the query outputted by the query control
means is received by the receiving means, controls the primary coil
so that the primary coil can be driven with an alternating
current.
[0021] Further, according to yet another embodiment of the present
invention, there is provided power-receiving equipment including: a
secondary coil incorporated to be stationary in the power-receiving
equipment; a sensing means that is located at a position at which
when the positional relationship between a primary coil
incorporated to be movable in a power feeder and the secondary coil
falls within a proper range, the sensing means can sense a query
outputted from the power feeder; a secondary coil direct-current
driving control means that when the power-receiving equipment is
placed on the power feeder, controls the secondary coil so that the
secondary coil is driven with a direct current in order to exert
attraction with respect to the primary coil which is driven with a
direct current in the power feeder; a notification information
output means that after the driving with a direct current is begun
by the secondary coil direct-current driving control means, if the
query is sensed by the sensing means, outputs notification
information; and a secondary coil alternating-current driving
control means that after the driving with a direct current is begun
by the secondary coil direct-current driving control means, if the
query is sensed by the sensing means, controls the secondary coil
so that electromotive force induced by the primary coil which is
driven with a direct current is exerted.
[0022] Further, according to still yet another embodiment of the
present invention, there is provided a power feeder including: a
mount on which power-receiving equipment is placed; a primary coil;
a moving means for making the primary coil movable; a sensing means
that is disposed so that the positional relationship to the movable
primary coil remains unchanged, and that is located at a position
at which when the positional relationship between the primary coil
and a secondary coil incorporated to be stationary in the power
feeder falls within a proper range, the sensing means can sense the
query outputted from the power-receiving equipment; a primary coil
direct-current driving control means that when the power-receiving
equipment is placed on the mount, as long as the primary coil is
made movable by the moving means, controls the primary coil so that
the primary coil is driven with a direct current over a certain
time length in order to exert attraction with respect to the
secondary coil driven with a direct current in the power-receiving
equipment; and a primary coil alternating-current driving control
means that after driving the primary coil with a direct current is
begun, if the query is sensed by the sensing means, controls the
primary coil so that the primary coil can be driven with an
alternating current.
[0023] Further, according to further another embodiment of the
present invention, there is provided power-receiving equipment
including: a secondary coil incorporated to be stationary in the
power-receiving equipment; a query output means that outputs a
query to outside using a predetermined medium so that whether the
positional relationship between the primary coil incorporated in
the power feeder and the secondary coil falls within a proper range
is decided; a secondary coil direct-current driving control means
that when the power-receiving equipment is placed on the power
feeder, controls the secondary coil so that the secondary coil is
driven with a direct current over a certain time in order to exert
attraction with respect to the primary coil which is driven with a
direct current; a query control means that after the secondary coil
is driven with a direct current by the secondary coil
direct-current driving control means, allows the query output means
to output a query; and a secondary coil alternating-current driving
control means that after the secondary coil is driven with a direct
current by the secondary coil direct-current driving control means,
controls the secondary coil so that electromotive force induced by
the primary coil which is driven with an alternating current is
exerted.
[0024] In the foregoing constitutions, a power feeder includes a
movable primary coil, and power-receiving equipment includes a
secondary coil. When the power-receiving equipment is placed on the
power feeder, the primary coil in the power feeder is driven with a
direct current, and the secondary coil in the power-receiving
equipment is driven with a direct current. Thus, attraction is
exerted between the coils. Accordingly, the movable primary coil is
attracted to the secondary coil, and has the position thereof
varied. As a result, if a decision is made that the positional
relationship between the primary coil and secondary coil has fallen
within a proper range, electromotive force induced by the primary
coil is exerted in the secondary coil by driving the primary coil
with an alternating current. Namely, power transmission is
initiated.
[0025] As mentioned above, according to the embodiments of the
present invention, when power-receiving equipment is placed on a
power feeder, the positions of a primary coil and a secondary coil
are automatically controlled to fall within a proper range, and
succeeding power feeding can be achieved appropriately. Therefore,
there is provided a power feeding system that exhibits high
universality and versatility and is user-friendly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a diagram showing an example of the fundamental
configuration of a non-contact charging system in accordance with
an embodiment;
[0027] FIG. 2 is a diagram showing a concrete example of a primary
coil moving mechanism, and a charger and equipment to be charged in
accordance with a first embodiment;
[0028] FIG. 3 is a block diagram showing an example of a system
configuration for the charger and equipment to be charged in
accordance with the first embodiment;
[0029] FIG. 4 is a flowchart showing an example of a processing
procedure for primary-coil positioning control to be executed by
the charger and equipment to be charged in accordance with the
first embodiment;
[0030] FIG. 5 is a diagram showing a concrete example of a primary
coil moving mechanism, and a charger and equipment to be charged in
accordance with a second embodiment;
[0031] FIG. 6 is a block diagram showing an example of a system
configuration for the charger and equipment to be charged in
accordance with the second embodiment;
[0032] FIG. 7 is a flowchart showing an example of a processing
procedure for primary-coil positioning control to be executed by
the charger and equipment to be charged in accordance with the
second embodiment;
[0033] FIG. 8 is a block diagram showing an example of a system
configuration for a charger and equipment to be charged in
accordance with a third embodiment;
[0034] FIG. 9 is a flowchart showing an example of a processing
procedure (first example of an algorithm) for primary-coil
positioning control to be executed by the charger and equipment to
be charged in accordance with the third embodiment; and
[0035] FIG. 10 is a flowchart showing an example of a processing
procedure (second example of an algorithm) for primary-coil
positioning control to be executed by the charger and equipment to
be charged in accordance with the third embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Modes for carrying out the present invention (hereinafter,
embodiments) will be described by sequentially following subjects
presented below.
[0037] <1. Fundamental Constitution of a Non-Contact Charging
System to which the Present Invention is Applied>
[0038] <2. First Embodiment> [0039] [1 Structure of a primary
coil moving mechanism] [0040] [2-2 System Configuration] [0041]
[2-3 Algorithm]
[0042] <3. Second Embodiment> [0043] [3-1 Structure of a
Primary Coil Moving Mechanism] [0044] [3-2 System Configuration]
[0045] [3-3 Algorithm]
[0046] <4. Third Embodiment> [0047] [4-1 System
Configuration] [0048] [4-2 Algorithm (First Example)] [0049] [4-3
Algorithm (Second Example)] <1. Fundamental Constitution of a
Non-Contact Charging System To which the Present Invention is
Applied>
[0050] FIG. 1 shows the fundamental constitution of a non-contact
charging system to which the present invention is applied.
[0051] As shown in FIG. 1, the non-contact charging system in
accordance with the embodiment includes a charger (power feeder) 1
and equipment to be charged 2 that is electronic equipment
(power-receiving equipment) which operates with a secondary
battery.
[0052] The equipment to be charged 2 shown herein is a digital
camera but will not be limited to the digital camera.
[0053] The charger 1 inputs, for example, a mains ac voltage and
feeds charging power to the equipment to be charged 2.
[0054] The equipment to be charged 2 operates with power fed from a
built-in secondary battery, and the built-in secondary battery is
charged with the charging power fed from the charger 1.
[0055] In the equipment to be charged 2, a secondary coil is
incorporated to be stationary at a predetermined position on the
bottom inside a housing 2a.
[0056] In this case, after the secondary coil 22 is attached to a
substrate 21, the substrate 21 is turned upside down and fixed to
the internal wall of the bottom of the equipment to be charged 2
using screws 40.
[0057] A sensor 23 is interposed between the secondary coil 22 and
the internal wall of the bottom of the housing 2a. The sensor 23
shall be an optical sensor that detects incident light. In reality,
the sensor 23 is attached to the substrate 21.
[0058] A light transmission part 2b is formed at a position on the
bottom of the housing 2a of the equipment to be charged opposed to
the position of the sensor 23, so that light coming from outside
the housing 2a can enter the sensor 23. As mentioned above, when
the sensor 23 receives light, if the wavelength (color) of light to
be received is predesignated, the light transmission part 2b may be
provided with a filtering capability for selectively transmitting
light of designated color.
[0059] The charger 1 has a primary coil 12 incorporated in a
housing 1a thereof.
[0060] For example, according to a related art, the primary coil 12
is incorporated to be stationary in the housing 1a.
[0061] In contrast, in the present embodiment, the primary coil 12
includes a primary coil moving mechanism 17 that is incorporated in
the housing 1a of the charger 1. The primary coil 12 can therefore
be moved in planar directions indicated with an arrow A. In the
drawing, the arrow A indicates the directions corresponding to the
sideways directions of paper. This is because the drawing is a
front view. Actual planer movements include movements freely made
in the directions at 360.degree.. A structure in which a movement
in a certain specific direction is restricted is not inconceivable.
The primary coil moving mechanism 17 ensures a certain distance L
that is long enough to permit proper transmission of power between
the secondary coil and primary coil as long as the primary coil 12
is actuated.
[0062] A light emitter 15 is disposed on the upper side of the
primary coil 12. The light emitter 15 is attached to a substrate
11. Light emanating from the light emitter 15 is irradiated to
outside via a light transmission part of the upper side of the
housing 1a, though it is not shown in the drawing.
[0063] The light emitter 15 can be moved together with the primary
coil 12 by the primary coil moving mechanism 17 while being fixed
to the substrate 11. Therefore, the light transmission part of the
housing 1a is preferably shaped to have a size that is large enough
to cover a movable range within which the light emitter 15 is
movable in the planar directions. When the wavelength (color) of
light is predesignated, the light transmission part of the charger
1 may have the filtering capability for selectively transmitting
the light of the designated color.
[0064] A power circuit that produces a current which flows into the
primary coil and uses a mains ac power supply as a power source,
and a control unit that includes a control processing unit (CPU)
and implements internal control are incorporated in the charger 1,
though they are not shown.
[0065] In the present embodiment, the primary coil 12 and secondary
coil 22 may be shaped like, for example, a winding or a sheet.
[0066] In the foregoing constitution, non-contact charging is
carried out as described below.
[0067] The equipment to be charged 2 shall be mounted on the
charger 1. The primary coil 12 of the charger 1 and the secondary
coil 22 of the equipment to be charged 2 shall have a distance L,
which falls within a permissible range, between them. A deviation
in a planar direction of the position of the primary coil from the
position of the secondary coil shall fall within a permissible
range within which power necessary for charging can be
transmitted.
[0068] In the foregoing state, in the charger 1, the primary coil
12 is driven with an alternating current. In other words, a defined
amount of alternating current to be used for charging is routed to
the primary coil 12. Accordingly, an ac magnetic flux is induced in
the primary coil 12, and induced electromotive force is exerted in
the secondary coil 22. Namely, power is transmitted from the
charger 1 to the equipment to be charged 2 by way of the primary
coil 12 and secondary coil 22. In the equipment to be charged 2,
charging power, for example, a constant current is produced owing
to the induced electromotive force exerted in the secondary coil,
and fed to the secondary battery. That is, the secondary battery is
charged.
[0069] According to the related art, when the equipment to be
charged 2 is placed on the charger 1, the foregoing charging
actions are initiated immediately.
[0070] In contrast, according to the present embodiment, when the
equipment to be charged 2 is placed on the charger 1, the primary
coil 12 and secondary coil 22 are controlled so that a positional
deviation in a planar direction falls within a permissible range.
In other words, the primary coil 12 is controlled to be positioned
with respect to the secondary coil 22.
[0071] Therefore, the charger 1 begins driving the primary coil 12
with a direct current with the primary coil 12 made movable by the
primary coil moving mechanism 17. Namely, a direct current is
caused to flow but an alternating current is not.
[0072] Concurrently, the equipment to be charged 2 begins driving
the secondary coil 22 with a direct current.
[0073] At this time, the polarities of currents that flow into the
primary coil 12 and secondary coil 22 respectively are designated
so that magnetic fields is induced to cause attraction to be
exerted between them.
[0074] As mentioned above, both the primary coil 12 and secondary
coil 22 are driven with a direct current so that attraction is
exerted between the primary coil 12 and secondary coil 22. The
primary coil 12 that is made movable by the primary coil moving
mechanism 17 is attracted to the position of the secondary coil 12.
A positioning control algorithm will be detailed later. Anyway, the
positional deviation in a planar direction finally falls within the
permissible range.
[0075] If a decision is made that the positional deviation in any
planar direction has fallen within the permissible range, the
positioning actions are switched to the aforesaid charging actions.
Namely, the primary coil 12 being driven with a direct current is
now driven with an alternating current, and the secondary coil 22
is set to a state in which the secondary coil can receive power
transmitted from the primary coil 12.
[0076] Since positioning is performed as mentioned above, the
necessity of designing the charger 1 and equipment to be charged 2
so that they have physical engagement or fitting facilitating
shapes for the purpose of positioning is obviated. Therefore,
limitations to be imposed on the equipment to be charged 2, which
can be charged by the charger 1, in terms of the shape are
alleviated. The universality of the charger 1 is improved.
[0077] According to the present embodiment, the primary coil
incorporated in the charger 1 is moved in order to automatically
achieve positioning. Accordingly, when a user places the equipment
to be charged 2 on the charger 1, the user is not requested to
place the equipment to be charged as accurately as that requested
in the patent document 4. Namely, a charging system in which even
when the equipment to be charged 2 is placed somewhat carelessly,
the equipment to be charged 2 is properly charged can be provided,
and can be easily dealt with by the user. Even when a guide or the
like helping place the equipment to be charged 2 is inscribed on
the charger 1, freedom in designing expands.
<2. First Embodiment>
[2-1 Structure of the Primary Coil Moving Mechanism]
[0078] Next, a first embodiment will be described below.
[0079] FIG. 2 shows the charger 1 and equipment to be charged 2 in
accordance with the first embodiment. In the first embodiment, the
primary coil moving mechanism 17 has a structure that will be
concretely described below.
[0080] In the primary coil moving mechanism 17 shown in FIG. 2, a
movable member bearing region is structured as a spherical-pieces
layer 17a.
[0081] The spherical-pieces layer 17a is formed by, for example,
juxtaposing numerous spherical pieces 30, which have a
predetermined diameter, in planar directions.
[0082] The substrate 11 to which the primary coil 12 is attached is
placed on the spherical-pieces layer 17a. At this time, a distance
L that is long enough to ensure necessary and sufficient magnetic
coupling is preserved between the primary coil 12 and the secondary
coil 22 incorporated in the equipment to be charged 2.
[0083] For forming the spherical-pieces layer 17a, spherical pieces
may be laid down nearly all over a disposition space for the
spherical pieces 30. Alternatively, the number of spherical pieces
30 exhibiting a certain density or less in the disposition space
may be placed so that the spherical pieces 30 can somewhat freely
roll. The latter is more preferable from the viewpoint of, for
example, minimizing friction against the substrate 11 to which the
primary coil 12 is attached.
[0084] The material of the spherical pieces 30 is not limited to
any specific one, but may be a ceramic, glass, or a resin. A
material that minimizes the friction of the surface of each of the
spherical pieces 30 is preferred. Owing to the adoption of such a
material, not only the contact parts of the spherical pieces with
respect to the substrate 11 become points but also the substrate 11
can be moved on the spherical-pieces layer 17a in the planar
directions with the friction against the substrate nearly
ignored.
[0085] The side of the substrate 11 that comes into contact with
the spherical-pieces layer 17a has to be finished as, for example,
a smooth plane.
[0086] [2-2 System Configuration]
[0087] FIG. 3 shows an example of a system configuration for the
charger 1 and equipment to be charged 2 in accordance with the
first embodiment.
[0088] The charger 1 is shown to include, in addition to the
primary coil 12, a primary-side control unit 13, a power control
unit 14, a light emitter 15, a primary-side receiving unit 16, and
an indicator 18.
[0089] The primary-side control unit 13 includes, for example, a
CPU and memories such as a RAM and a ROM (or a flash memory), and
autonomously implements control in the charger 1.
[0090] The power control unit 14 controls driving of the primary
coil 12 in response to an instruction given by the primary-side
control unit 13.
[0091] The light emitter 15 is, as shown in FIG. 2, physically
incorporated to be stationary at, for example, a position closest
to the bottom of the housing 2a while being attached to the
substrate 21. The light emitter 15 is driven to emit light by the
primary-side control unit 13.
[0092] The light emitter 15 is, in practice, realized with a
light-emitting diode, a phototransistor, or a laser element.
[0093] Light emanating from the light emitter 15 is, as seen from a
description to be made later, an output (a query) to be used to
decide whether the positional relationship between the primary coil
12 and secondary coil 22 falls within a proper range. The reason
why light is adopted as the medium that carries the query is that
light is not incorrectly sensed while being adversely affected by
magnetic fluxes induced by driving the primary coil 11 and
secondary coil 22.
[0094] The primary-side receiving unit 16 is a region that receives
a signal which is transmitted wirelessly from a secondary-side
notification unit 33 to be described later and which acknowledges
receipt of light. On receipt of the signal, the primary-side
receiving unit 16 notifies the primary-side control unit 13 of the
fact.
[0095] The indicator 18 has, for example, a certain number of
light-emitting elements, which have different colors, bared on the
housing 1a so that a user can discern the emitted light.
[0096] The primary-side control unit 13 selects any of the colors
of the light-emitting elements according to an operating state to
be notified, and drives the light-emitting element of the selected
color as the indicator 18. A user sees the thus displayed indicator
18 so as to learn the operating state of the charging system.
[0097] In this case, the charger 1 operates with a mains ac voltage
AC.
[0098] As for the configuration of the equipment to be charged 2,
there are shown, in addition to the secondary coil 22, a
secondary-side control unit 31, a secondary battery 32, a sensor
23, and a secondary-side notification unit 33.
[0099] The secondary-side control unit 31 includes a microcomputer
which includes a CPU and memories such as a RAM and a ROM (or a
flash memory), and a power control circuit, and can implement
control in charging actions to be performed in the equipment to be
charged.
[0100] The equipment to be charged 2 has, as shown in FIG. 3, the
secondary battery 32 incorporated therein, and can operate with dc
power fed from the secondary battery 32. In this case, the
secondary-side control unit 31 inputs induced electromotive force
exerted in the secondary coil 22 so as to produce a charging
current, and feeds the charging current to the secondary battery
32. Thus, the secondary battery 32 is charged. In this case, the
secondary-side control unit 31 can sense the amount of charge,
which is stored in the secondary battery 32, on the basis of the
voltage across the secondary battery 32. When sensing that the
secondary battery 32 is fully charged, the secondary-side control
unit 31 discontinues conduction of a current to the secondary coil
22 so as to cease driving. This prevents the fully-charged
secondary battery 32 from being further charged.
[0101] The sensor 23 is a region that receives and detects light
emanating from the light emitter 15 of the charger 1. As the sensor
23, various light detecting elements including, for example, a
phototransistor can be adopted.
[0102] The sensor 23 can operate with conduction of a current from,
for example, the secondary-side control unit 31. A detection signal
the sensor 23 outputs after sensing light is fetched by the
secondary-side control unit 31.
[0103] The secondary-side notification unit 33 is a region that,
under the control of the secondary-side control unit 31, wirelessly
notifies in a non-contact manner the primary-side receiving unit 16
of the charger 1 of the fact that the sensor 23 of the equipment to
be charged 2 has sensed light.
[0104] For transmitting a signal from the primary-side receiving
unit 16 to the secondary-side notification unit 33, for example, a
pulse, a frequency-modulated wave, or light may be adopted as the
signal. These media are unsusceptible to or are not affected by
magnetic fluxes induced by coils. The media other than light may be
adopted as an intermediary between the light emitter 15 and sensor
23.
[0105] Conceivably, one communication unit having the capabilities
of the light emitter 15 and primary-side receiving unit 16 may be
included in the charger 1, and one communication unit having the
capabilities of the sensor 23 and secondary-side communication unit
may be included in the equipment to be charged 2, so that the
communication units may communicate with each other.
[0106] [2-3 Algorithm]
[0107] The flowchart of FIG. 4 shows an example of a processing
procedure to be followed by the charger 1 and the equipment to be
charged 2 for the purpose of positioning control concerning a
charging position (the position of the primary coil 12) prior to
beginning of charging. The pieces of processing described in the
chart may be regarded as pieces of processing which the CPU serving
as the primary-side control unit 13 of the charger 1 and the CPU
serving as the secondary-side control unit 31 of the equipment to
be charged 2 execute according to programs. The program data items
may be stored and preserved in, for example, a recording medium, or
may be preserved at a server on a network.
[0108] In the charger 1, the primary-side control unit 13 decides
at step S101 whether the equipment to be charged 2 is placed on the
charger 1. For the decision making, a mechanical switch to be
depressed when the equipment to be charged 2 is placed, or a sensor
that is realized with a piezoelectric element and senses a change
in a pressure occurring due to the weight of the equipment to be
charged 2 when the equipment to be charged 2 is placed is included.
Otherwise conceivable is a constitution in which, light is
irradiated to outside by a light-emitting element, and light
reflected from the equipment to be charged 2 when the equipment to
be charged 2 is placed is detected by an optical sensor. A decision
is made based on the output of the switch or sensor.
[0109] If a decision is not made at step S101 that the equipment to
be charged 2 has been placed, for example, the processing described
in the drawing may be abandoned, and step S101 may be resumed at
the right timing.
[0110] In contrast, if a positive result of decision is obtained at
step S101 because the equipment to be charged 2 has been placed,
the primary-side control unit 13 proceeds to a procedure beginning
at step S102.
[0111] Herein, the region (mount) of the charger 1 on which the
equipment to be charged 2 is placed shall not be designed to, for
example, have a physical engagement facilitating shape so as to
strictly restrict the mounting position of the equipment to be
charged 2 on the charger 1. For example, an alignment mark or the
like is not intended to strictly indicate a position but is an
indication that tolerates a deviation to some extent. According to
the present embodiment, when a user places the equipment to be
charged 2 on the charger 1, the user may not strictly be conscious
of the position. The charger 1 is easy to handle. In addition, if
the charger is, for example, flattened at a position at which the
equipment to be charged 2 is placed, the universality and
versatility thereof would improve.
[0112] The shape or design of the region of the charge on which the
equipment to be charged 2 is placed may be varied depending on the
shape or design of the equipment to be charged 2 or a range within
which the charger has to be versatile. The freedom in determining
the shape or design is highly expandable. Therefore, introduction
of a concrete example will be omitted.
[0113] As long as the aforesaid form of a mount is adopted, when a
positive result of decision is obtained because the equipment to be
charged 2 has been placed, a deviation in a planar direction of the
position of the primary coil 12 from the position of the secondary
coil 22 may exceed a permissible range (proper range). In the
present invention, positioning is, as described later, controlled
in order to correct the positional deviation.
[0114] At step S102, the primary-side control unit 13 causes
driving of the primary coil 12 with a direct current to begin.
Namely, the primary-side control unit 13 allows an action of
feeding a predetermined amount of direct current to the primary
coil 12 to begin.
[0115] Along with the beginning of the driving with a direct
current at step S102, the primary-side control unit 13 drives the
light-emitting element included in the indicator 18 according to a
pattern for a predetermined color or a light-emitting pattern (for
example, lighting or flickering) so that a notification signifying
that the position of the primary coil (charging position) is being
determined will be displayed.
[0116] Thereafter, at step S104, the primary-side control unit 13
stands by until a standby time Tw elapses. During a period during
which the primary-side control unit 13 stands by at step S104,
driving the primary coil 12 with a direct current at step S102, and
a notification signifying that positioning is in progress is still
displayed as it is at step S103. If a decision is made at step S104
that the standby time Tw has elapsed, the primary-side control unit
13 proceeds to step S105.
[0117] At step S105, the primary-side control unit 13 ceases the
driving of the primary coil 12 with a direct current. For ceasing
the driving with a direct current, for example, conduction of a
direct current for driving to the primary coil 12 is
discontinued.
[0118] While the processing of step S105 is in progress, the
primary-control unit 13 executes driving of the light emitter 15 at
step S107 so as to cause the light emitter 15 to emit light. For
driving the light emitter 15 to cause the light emitter 15 to emit
light at step S107, for example, when a certain time (for example,
two or three sec at most) has elapsed since the light emitter 15 is
allowed to begin emitting light, the light emission is ceased.
[0119] As for another way of causing the light emitter 15 to emit
light, the light emitter 15 may be allowed to begin emitting light
at step S107, and the light emission may be continued until a
positive result of decision is obtained at step S107 because
positioning has succeeded. However, in this case, since the time
during which the light emitter 15 is allowed to emit light is long,
the power consumption increases. Especially, although the light
emitter 15 exhibiting a sharp directivity angle is advantageous, as
the directivity angle gets larger, a light-emitting diode or the
like employed in the light emitter 15 is requested to offer high
luminance. Higher luminance leads to higher power consumption.
Light emanating from the light emitter 15 has to pass through two
light transmission parts, that is, the light transmission part of
the charger 1 and the light transmission part 2b of the equipment
to be charged 2. The high luminance is requested in consideration
of attenuation in light intensity derived from passage through the
two light transmission parts.
[0120] In consideration of the foregoing matters, the light
emission time during which the light emitter 15 emits light at step
S107 is set to a short time in this embodiment. Although the light
emitter 15 is driven to emit light for the short time, the time
during which light is sensed in the equipment to be charged 2
includes the light emission time for the light emitter 15 or is set
to a time longer than the light emission time. Therefore, once
positioning succeeds, light can be properly sensed.
[0121] In the equipment 2 to be charged, the secondary-side control
unit 31 decides at step S201 whether the equipment to be charged 2
has been placed on the charger 1. For the decision, similarly to
that in the charger 1, a mechanical switch or sensor is included in
the equipment to be charged 2. The output of the switch or sensor
is used to make a decision.
[0122] If a negative result of decision is obtained at step S201
because the equipment to be charged 2 has not been placed on the
charger 1, the secondary-side control unit 31 terminates the pieces
of processing described in the drawing, and resumes step S201 at
the right timing.
[0123] In contrast, if a positive result of decision is obtained
because the equipment to be charged 2 has been placed, the
secondary-side control unit proceeds to step S202 or a subsequent
step.
[0124] At step S202, the secondary-side control unit 31 causes
driving of the secondary coil with a direct current to begin.
[0125] In this case, the timing at which a positive result of
decision is obtained at step S101 in the charger 1 is thought to
coincide with the timing at which a position result of decision is
obtained at step S201 in the equipment to be charged 2.
Accordingly, the timing at which driving the primary coil 12 with a
direct current is begun at step S102 in the charger 1 is thought to
coincide with the timing at which driving the secondary coil with a
direct current is begun at step S202 in the equipment to be charged
2.
[0126] In the charger 1, driving the primary coil 12 with a direct
current is continued over the time length of the standby time Tw at
step S104 after the driving is begun at step S102. The equipment to
be charged 2 begins driving the secondary coil 22 with a direct
current at step S202. Therefore, the secondary coil 22 is still
driven with a direct current during the time interval corresponding
to the standby time Tw.
[0127] When a direct current is caused to flow into a coil,
magnetic force is induced with the polarity thereof fixed based on
the polarity of the direct current. In the present embodiment, the
polarity of a direct current with which the primary coil 12 is
driven at step S102, and the polarity of a direct current with
which the secondary coil 22 is driven at step S202 are determined
so that attraction is exerted by the magnetic force induced by the
primary coil and the magnetic force induced by the secondary coil
22.
[0128] Therefore, the primary coil 12 and secondary coil 22 are
attracted to each other. Specifically, the secondary coil is held
stationary in the housing 2a, while the primary coil 12 is movable
in the planar directions within the housing 1a owing to the primary
coil moving mechanism 17. Therefore, when the primary-side control
unit stands by over the standby time Tw at step S104, the primary
coil 12 is moved to the position of the secondary coil 22 while
being attracted to the secondary coil 22. The movement may be
regarded as a movement for correcting the positional relationship
in a planar direction between the primary coil 12 and secondary
coil 12 for the purpose of improving the transmission
efficiency.
[0129] When the standby over the standby time Tw is completed at
step S104, the charger 1 discontinues conduction of a current so as
to cease driving of the first coil 12 with a direct current at step
S105. Therefore, even when the secondary coil 22 is kept driven
with a direct current, since the primary coil 12 does not have
transmission power. Therefore, the primary coil 12 neither induces
magnetic force of fixed polarity nor functions as a magnet.
Therefore, neither attraction nor repulsion is exerted between the
primary coil 12 and secondary coil 22.
[0130] For example, when attraction is exerted between the primary
coil 12 and secondary coil 22, the primary coil 12 is recognized as
being movable anytime due to the attraction to the secondary coil.
In the present embodiment, after the primary coil 12 is made
movable over a certain time corresponding to the standby time Tw,
conduction of a current to the primary coil 12 is discontinued at
step S105 in order to nullify the attraction. The position of the
primary coil 12 is finalized.
[0131] In the charger 1, attraction is canceled as mentioned above,
and the position of the primary coil 12 is finalized. In this
state, the light emitter 15 emits light at step S107.
[0132] In the equipment to be charged 2, the secondary-side control
unit 31 causes driving of the secondary coil with a direct current
to begin at step S202. At step S203, the secondary-side control
unit 31 stands by until the sensor 23 senses light.
[0133] In the charging system of the present embodiment, a degree
of magnetic coupling between the primary coil 12 and secondary coil
22 that is high enough to achieve proper charging is attained when:
the primary coil 12 and secondary coil 22 have such a positional
relationship that the distance L shown in FIG. 1 is preserved; and
a proper range (permissible range) of values of a deviation of a
center of a magnetic flux (center of a coil) in a planar direction
is 4 mm or less.
[0134] Accordingly, the present embodiment is structured so that
unless the deviation in a planar direction of the position of the
primary coil 12 from the position of the secondary coil 22 falls
within 4 mm, light emanating from the light emitter 15 is not
effectively detected by a photo-receiver after entering through the
light transmission part 2b of the equipment to be charged 2.
[0135] The foregoing structure is realized by adjusting, for
example, the directivity angle of light emanating from the light
emitter 15, the size or shape of the light transmission part 2b, or
the directivity angle of light received by the sensor 23.
[0136] When the light emitter 15 is caused to emit light at step
S107, if the primary coil 12 is located at a distance of 4 mm or
less from the secondary coil 22, the sensor 23 can sense light
emanating from the light emitter 15. The detection output is fed to
the secondary-side control unit 31. Accordingly, the secondary-side
control unit 31 obtains a positive result of decision at step S203,
and proceeds to step S204.
[0137] At step S204, the secondary-side control unit 31 controls
the secondary-side notification unit 33, and allows the
secondary-side notification unit 33 to transmit a signal notifying
that the equipment to be charged 2 has received light emanating
from the light emitter 15.
[0138] In contrast, when the light emitter 15 is caused to emit
light at step S107, if the deviation in a planar direction of the
position of the primary coil 12 from the position of the secondary
coil 22 exceeds 4 mm, the sensor 23 fails to sense light emanating
from the light emitter 15. In this case, a negative result of
decision is obtained at step S203. The secondary-side control unit
31 stands by until light is sensed.
[0139] In the charger 1, the primary-side control unit 13 drives
the light emitter 15 so as to allow the light emitter 15 to emit
light at step S106, and then proceeds to step S107. At step S107,
the primary-side control unit 13 decides whether a notification
signifying that light has been received and being transmitted at
step S204 has been received by the primary-side receiving unit
16.
[0140] If a negative result of decision is obtained because a
notification signifying that light has been received has not been
received at step S107, the primary-side control unit 13 proceeds to
step S110 or a subsequent step.
[0141] When a negative result of decision is obtained at step S107,
it means that: the primary coil 12 and secondary coil 22 are made
electromagnetic over the time length of the standby time Tw at step
S102 to step S104 and step S202; and the primary coil 12 is
attached to the secondary coil 22 and thus made movable; but the
deviation of the position of the primary coil 12 from the position
of the secondary coil 22 does not fall within the permissible
range.
[0142] In this case, at step S110, whether the number of times of
repetition by which actions are repeated at step S102 to step S104
has reached a defined number of times is decided. If a negative
result of decision is obtained, the primary-side control unit 13
returns to step S102.
[0143] Accordingly, the primary coil 12 is driven with a direct
current during the period corresponding to the standby time Tw. At
this time, in the equipment to be charged 2, driving the secondary
coil 22 with a direct current is continued after it is begun at
step S202.
[0144] Therefore, attraction is exerted between the primary coil 12
and secondary coil 22 during the period corresponding to the
standby time Tw. The primary coil 12 is thus made movable while
being attached to the secondary coil 22. Thereafter, driving the
primary coil 12 with a direct current is ceased at step S105 and
the light emitter 15 is driven to emit light at step S107.
Eventually, the primary coil 12 approaches the secondary coil 22,
and the position of the primary coil 12 is thus shifted.
[0145] As mentioned above, in the present embodiment, actions to be
performed to drive the primary coil 12 and secondary coil 12 with a
direct current over the certain time (Tw) for the purpose of making
the coils electromagnetic so that the coils is attracted to each
other are repeated in order to establish a state in which the
deviation in a planar direction of the position of the primary coil
12 from the position of the secondary coil 22 falls within the
permissible range.
[0146] As a result of repetition of the actions, the deviation in a
planar direction of the position of the primary coil 12 from the
position of the secondary coil 22 falls within the permissible
range at a certain step. Light emanating from the light emitter 15
is then received by the sensor 23. As a result, a positive result
of decision is obtained at step S107.
[0147] If a positive result of decision is obtained at step S107,
the primary-side control unit 13 proceeds to step S108 or a
subsequent step.
[0148] At step S108, the primary-side control unit 13 controls the
indicator 18 so that the fact that positioning control has
succeeded is notified. Concurrently, at step S110, the primary-side
control unit 13 causes the driving of the light emitter 15, which
has been carried on for light emission, to cease.
[0149] At step S109, the primary-side control unit 13 causes
driving of the primary coil 12 with an alternating current to begin
according to an amount of current and a frequency corresponding to
those employed in the charging actions. Namely, the primary-side
control unit 13 feeds an alternating current to the primary coil 12
by the defined amount of current at the defined frequency.
[0150] For example, as the timing of driving the primary coil 12
with an alternating current, the timing other than the timing
succeeding the success in positioning achieved at step S108 is
conceivable. For example, at a step succeeding step S105 at which
driving the primary coil 12 with a direct current is ceased, the
driving with a direct current may be switched to driving with an
alternating current. In other words, the driving with a direct
current is switched to the driving with an alternating current at a
step preceding the success in positioning. However, power is not
appropriately transmitted until positioning succeeds. Meanwhile,
driving the primary coil 12 with an alternating current is
insignificant. In the algorithm shown in FIG. 4, consideration is
taken into this point. Namely, the primary coil is not driven with
an alternating current until positioning succeeds. Therefore, for
example, the power consumption caused by the driving with an
alternating current to be performed at the step preceding the
success in positioning can be avoided.
[0151] In the equipment to be charged 2, the secondary-side control
unit 31 senses light at step S203 and notifies at step S204 of the
fact that light has been received. Thereafter, at step S205, the
secondary-side control unit 31 drives the secondary coil 22 with an
alternating current. Therein, when it says that the secondary coil
22 is driven with an alternating current, it means that a current
is conducted to the secondary coil 22 so that electromotive force
induced by driving the primary coil 12 with an alternating current
is exerted in the secondary coil 22.
[0152] At this time, in the charger 1, driving the primary coil 12
with an alternating current for charging has begun. Therefore, when
the secondary coil 22 is driven with an alternating current at step
S205, induced electromotive force is exerted. At step S206, the
secondary-side control unit 31 initiates the action of inputting
the induced electromotive force from the secondary coil 22 so as to
produce a charging current and feed the charging current to the
secondary battery. In short, the secondary-side control unit 31
begins charging the secondary battery 32.
[0153] Along with the beginning of charging, at least one of the
charger 1 and equipment to be charged 2 should begin displaying a
notification indicating that charging is in progress. However, an
amount of charge stored in the secondary battery 32 can be
identified by the equipment to be charged 2. Therefore, when the
equipment to be charged 2 displays the notification signifying that
charging is in progress, the series of actions is completed by the
equipment to be charged 2. For example, a progress of increasing
the amount of charge can be indicated, or a notification signifying
completion of charging can be displayed.
[0154] As described previously, in the present embodiment, a
charging-position correcting action is repeated by repeatedly
exerting attraction with magnetic forces induced by the primary
coil 12 and secondary coil 22 over a certain time (Tw) in order to
attract the primary coil 12 to the secondary coil 22.
[0155] However, in some cases, even if the charging-position
correcting action is repeated many times, the deviation in a planar
direction of the position of the primary coil 12 from the position
of the secondary coil 22 does not fall within the permissible range
for some reason.
[0156] In this case, the number of times of repetition by which
returning from step S110 to step S102 is repeated reaches a defined
number of times. A positive result of decision is therefore
obtained at step S110. The processing of step S111 is therefore
carried out.
[0157] At step S111, the primary-side control unit 13 drives the
indicator 18 so that the fact that positioning control has failed
(error) is notified.
[0158] For example, assume that the indicator 18 displays a
notification signifying that positioning has failed and a user has
recognized the fact. In this case, for example, the user lifts the
equipment to be charged 2 apart from the charger 1, and then
re-places the equipment to be charged 2 on the charger 1. This
causes the charger 1 (primary-side control unit 13) and equipment
to be charged 2 (secondary-side control unit 31) to resume the
pieces of processing beginning at step S101 or step S201. Namely,
positioning control is executed again.
[0159] In the present embodiment, a period during which the primary
coil 12 and secondary coil 22 are concurrently driven with a direct
current is defined for positioning control. Therefore, in the
present embodiment, unlike, for example, the patent document 1,
attraction can be reliably exerted between the primary coil 12 and
secondary coil 22. If a decision is made that the deviation of the
position of the primary coil 12 from the position of the secondary
coil 22 falls within the permissible range through positioning
control, the driving with a direct current is switched to driving
with an alternating current, and charging actions are initiated
appropriately.
<3. Second Embodiment>
[3-1 Structure of a Primary Coil Moving Mechanism]
[0160] FIG. 5 shows the charger 1 and equipment to be charged 2
included in a non-contact charging system in accordance with the
second embodiment. In the drawing, the same reference numerals are
assigned to components identical to those shown in FIG. 1 and FIG.
2. An iterative description will be omitted.
[0161] In the second embodiment, the primary coil moving mechanism
17 has a structure described below. Specifically, as illustrated,
the primary coil moving mechanism 17 has the structure that an
electromagnet 17b is disposed as a movable member bearing region
below the substrate 11 to which the primary coil 12 is
attached.
[0162] In order to make the primary coil 12 movable using the
primary coil moving mechanism 17, the primary coil 12 is driven
with a direct current so that the primary coil 12 induces magnetic
force, and a current is conducted to the electromagnet 17b so that
the electromagnet 17b induces magnetic force. At this time, the
polarity of the magnetic force induced by the primary coil 12 and
the polarity of the magnetic force induced by the electromagnet 17b
are determined so that repulsion is exerted between the primary
coil and electromagnet 17b. The primary coil 12 and electromagnet
17b are thus driven.
[0163] Since the repulsion is exerted between the primary coil 12
and electromagnet 17b, the substrate 11 to which the primary coil
12 is attached nearly floats above the surface of the electromagnet
17b. When the substrate 11 to which the primary coil 12 is attached
floats, the lower-side surface of the substrate 11 hardly generates
friction against the surface of the electromagnet 17b. Therefore,
the primary coil 12 attached to the substrate 11 becomes movable in
planar directions.
[0164] Preferably, the electromagnet 17b has a size and a shape
permitting the substrate 11, to which the primary coil 12 is
attached, to float due to the repulsion over a movable range within
which the primary coil 12 is movable in the planar directions.
[0165] For positioning control, as mentioned above, repulsion is
exerted between the primary coil 12 and electromagnet 17b in order
to make the primary coil 12 movable. Concurrently, a direct current
having the polarity that causes attraction to be exerted with
respect to the primary coil 11 is, similarly to that in the first
embodiment, fed to the secondary coil 12, whereby the secondary
coil is driven with the direct current.
[0166] In this state, the primary coil 12 moves to approach the
secondary coil 12. Namely, the primary coil 12 is aligned with the
secondary coil 12.
[0167] FIG. 5 explicitly shows a state in which the substrate 11 to
which the primary coil 12 is attached floats due to the repulsion
exerted with respect to the electromagnet 17b. However, in reality,
even when the substrate 11 floats due to the repulsion, the
distance between the upper-side surface of the electromagnet 17b
and the lower-side surface of the substrate 17 which are opposed to
each other is very short.
[0168] In consideration of the above description, the surfaces of
the electromagnet 17b and substrate 11 which are opposed to each
other are preferably finished as smooth surfaces devoid of
irregularities or roughness.
[3-2 System Configuration]
[0169] FIG. 6 shows an example of a system configuration for the
charger 1 and equipment to be charged 2 in accordance with the
second embodiment.
[0170] In the drawing, the same reference numerals are assigned to
components identical to those shown in FIG. 3. An iterative
description will be omitted.
[0171] As for the configuration of the charger 1 in accordance with
the second embodiment, as illustrated, the charger 1 has the
electromagnet 17b thereof driven by the primary-side control unit
13. The configuration of the equipment to be charged 2 is identical
to that shown in FIG. 3.
[0172] [3-3 Algorithm]
[0173] The flowchart of FIG. 7 shows an example of a processing
procedure to be followed by the charger 1 and equipment to be
charged 2 in accordance with the second embodiment for the purpose
of positioning control. Even in this drawing, the same step numbers
are assigned to steps (pieces of processing) having the same
contents at those shown in FIG. 4. An iterative description will be
omitted.
[0174] As additional processing to be performed by the charger 1
and shown in the drawing, when a decision is made at step S101 that
the equipment to be charged 2 has been placed on the charger 1,
driving the electromagnet 17b is begun at step S101-1.
[0175] Driving the primary coil with a direct current is ceased at
step S105. Concurrently, ceasing driving of the electromagnet 17b
begun at step S101-1 is performed as additional processing at step
S105-1.
[0176] The steps other than the step S101-1 and step S105-1 to be
executed by the charger 1 are identical to those shown in FIG.
4.
[0177] The pieces of processing to be performed by the equipment to
be charged 2 are identical to those shown in FIG. 4.
[0178] According to the foregoing algorithm, when a decision is
made at step S101 that the equipment to be charged 2 has been
placed on the charger 1, the primary coil 12 is driven with a
direct current at step S102, and the electromagnet 17b is driven at
step S101-1. This causes the primary coil moving mechanism 17 to
function as described in conjunction with FIG. 5. The primary coil
12 is made movable in planar directions. In this state, the
primary-side control unit stands by over the standby time Tw at
step S104. At this time, since the secondary coil 22 of the
equipment to be charged 2 is driven with a direct current at step
S202, attraction is exerted between the primary coil 12 and
secondary coil 22. Therefore, during a period corresponding to the
standby time Tw, the primary coil 12 moves to approach the
secondary coil 22 while being attracted to the secondary coil.
[0179] After the standby time Tw elapses at step S104, driving the
electromagnet 17b is ceased at step S105-1, and driving the primary
coil 12 with a direct current is switched to driving with an
alternating current at step S106. Therefore, the attraction between
the primary coil 12 and secondary coil 22 disappears. Further,
repulsion between the primary coil 12 and electromagnet 17b
disappears. Eventually, the substrate 11 to which the primary coil
12 is attached stands still due to the own weight. The position of
the substrate 11 is finalized.
[0180] The pieces of processing succeeding step S107 are identical
to those shown in FIG. 4. In addition, the pieces of processing
succeeding step S203 and being performed by the equipment to be
charged 2 are identical to those shown in FIG. 4.
[0181] In the second embodiment and aforesaid first embodiment,
display of a notification to be performed at step S103 in order to
indicate that positioning is in progress, display of a notification
to be performed at step S108 in order to indicate that positioning
has succeeded, and display of a notification to be performed at
step S111 in order to indicate that positioning has failed as an
error are achieved using the indicator 18 composed of
light-emitting elements, for example, LEDs. However, when the
charger 1 is provided with a device capable of achieving more
advanced display, such as, a liquid crystal display unit, the
notifications can be displayed according to, for example, the
segment display method or the matrix driving image display
method.
[0182] In the second embodiment and aforesaid first embodiment,
charging-related display may be carried out by the equipment to be
charged 2 (not shown in FIGS. 4 and 7). Conceivable as display to
be performed by the equipment to be charged 2 is display indicating
that charging is in progress and being performed when charging is
begun at step S206. Further, display indicating that the secondary
battery 32 has been fully charged may be performed as a result of
monitoring an amount of charge stored in the secondary battery 32.
The display may be achieved by, for example, lighting an LED or the
like. Otherwise, a liquid crystal display unit or the like may be
used to provide display indicating stepwise the amount of
charge.
[0183] Further, in the second embodiment and aforesaid first
embodiment, display of a notification to be performed at step S103
in order to indicate that positioning is in progress, display of a
notification to be performed at step S108 in order to indicate that
positioning has succeeded, and display of a notification to be
performed at step S111 in order to indicate that positioning has
failed as an error may be executed by the equipment to be charged
2.
[0184] As for the notification signifying that positioning is in
progress, the equipment to be charged 2 may display it while
performing driving of the secondary coil with a direct current at
step S202. The notification signifying that positioning has
succeeded may be displayed responsively to the fact that light has
been sensed at step S203. As for the notification signifying that
positioning has failed as an error, for example, after driving the
secondary coil 22 with a direct current is begun at step S202, even
when a predetermined time that is long enough to decide that a
positioning error has occurred has elapsed, if light is not sensed
at step S203, the notification may be displayed.
[0185] The foregoing notifications may be displayed using, for
example, characters or icons. Further, the notifications may not be
displayed but may be outputted in the form of a sound.
<4. Third Embodiment>
[0186] [4-1 System configuration]
[0187] FIG. 8 shows an example of a system configuration for the
charger 1 and equipment to be charged 2 in accordance with a third
embodiment.
[0188] In the drawing, the same reference numerals are assigned to
components identical to those shown in FIG. 3 and FIG. 6. An
iterative description will be omitted.
[0189] In the system configuration of the third embodiment, the
primary coil moving mechanism 17 has the structure that includes
the spherical-pieces layer 17a and that is employed in the first
embodiment.
[0190] However, the configuration of the third embodiment can be
applied to a system in which the primary coil moving mechanism 17
includes the electromagnet 17b similarly to that employed in the
second embodiment. In this case, the primary-side control unit 13
of the charger 1 drives the electromagnet 17b.
[0191] For example, in the aforesaid first and second embodiments,
as shown in FIG. 1, FIG. 2, and FIG. 5, the charger 1 includes the
light emitter 15, and the equipment to be charged 2 includes the
sensor 23.
[0192] In contrast, in the third embodiment, the equipment to be
charged 2 includes a light emitter 35, and the charger 1 includes a
sensor 19.
[0193] The light emitter 35 is attached to the substrate 21 in
place of the sensor 23 shown in FIG. 1, and the sensor 19 is
attached to the substrate 11 in place of the light emitter 15,
though a structural illustration is omitted.
[0194] In FIG. 8, the primary-side control unit 13 of the charger 1
conducts a current to the sensor 19 so as to thus actuate the
sensor 19, and fetches a detection signal the sensor 19 outputs
after sensing light.
[0195] In the equipment to be charged 2, the light emitter 35 is
driven to emit light by the secondary-side control unit 31.
[0196] The communication means that notifies the fact that receipt
of light has been sensed and is shown in FIG. 3 and FIG. 6 to
include the primary-side receiving unit 16 of the charger 1 and the
secondary-side notification unit 34 of the equipment to be charged
can be excluded.
[0197] In the third embodiment, since the communication means can
be excluded, the internal configurations of the charger 1 and
equipment to be charged 2 can be simplified accordingly. Therefore,
the freedom in designing can be expanded, and a reduction in cost
can be expected.
[4-2 Algorithm (First Example)]
[0198] The first example of an algorithm to be followed by the
charger 1 and equipment to be charged 2 included in the third
embodiment having the aforesaid system configuration will be
described below.
[0199] The flowchart of FIG. 9 shows as the algorithm of the first
example an example of a processing procedure to be followed by the
charger 1 and equipment to be charged 2.
[0200] The pieces of processing to be performed by the charger 1
(primary-side control unit 31) at step S301 to step S305 are
identical to those shown in FIG. 4.
[0201] At step S306, driving the primary coil 12 with an
alternating current is begun. In conjunction with FIG. 4, a
description has been made of a case where driving the primary coil
12 with an alternating current may be begun at a step preceding a
step at which a decision is made that positioning has succeeded. In
FIG. 9, the case is explicitly described as step S306.
[0202] In the equipment to be charged 2, when the secondary-side
control unit 31 decides at step S401 that the equipment to be
charged has been placed on the charger, the secondary-side control
unit 31 drives the secondary coil 22 with a direct current at step
S402. Concurrently, in the third embodiment, at step S403, the
secondary-side control unit stands by until the standby time Tw
elapses.
[0203] The processing of step S403 is, similarly to the processing
of step S402, regarded as the processing that is immediately
performed when a positive result of decision is obtained at step
S401. Likewise, the processing of step S304 to be performed by the
charger 1 is, similarly to the pieces of processing of step S302
and step S303, regarded as the processing to be immediately
performed when a positive result of decision is obtained at step
S301. In other words, the timing at which the standby over the
standby time Tw begun by the charger 1 at step S304 is terminated
nearly coincides with the timing at which the standby over the
standby time Tw begun by the equipment to be charged 2 at step S403
is terminated.
[0204] When the standby time Tw elapses at step S403, the
secondary-side control unit 31 of the equipment to be charged 2
drives at step S404 the light emitter 35 so as to thus allow the
light emitter 35 to emit light over a certain time length.
[0205] When the standby time Tw elapses at step S304, the
primary-side control unit 13 of the charger 1 switches the driving
of the primary coil 12 with a direct current to the driving thereof
with an alternating current at step S305 and step S306, and then
proceeds to step S307. At step S307 and step S308, the primary-side
control unit 13 stands by over a standby time Tw2 of a
predetermined time length until light is sensed by the sensor 19.
The processing of step S307 is recognized as being immediately
performed when the pieces of processing of step S305 and step S306
are carried out after the standby time Tw elapses at step S304.
Therefore, the timing at which the light emitter 35 included in the
equipment to be charged 2 begins emitting light at step S404 nearly
coincides with the timing at which deciding whether light is sensed
is begun at step S307.
[0206] To be more specific, the execution time for the pieces of
processing of step S302 to step S305 can be predesignated, that is,
can be obtained as a known value. The standby time Tw that elapses
at step S403 is designated in consideration of the execution time
for the pieces of processing of step S302 to step S305 and the
processing time that elapses at step S402 (in this case, the
standby time may not be equal to the standby time Tw that elapses
at step S304). Thus, the timing of step S307 coincides with the
timing of step S404. Therefore, the timing at which the standby
over the standby time Tw begun at step S304 is terminated nearly
coincides with the timing at which the standby over the standby
time Tw begun by the equipment to be charged 2 at step S403 is
terminated.
[0207] The standby time Tw2 that elapses at step S308 is designated
to be equal to the time length from when the light emitter 35 is
driven to emit light at step S404 as processing to be performed in
the equipment to be charged 2 to when a standby time Tw1 elapses at
step S407.
[0208] In the charger 1, when light is sensed by the sensor 19
until the standby time Tw2 elapses, a positive result of decision
is obtained at step S307. The primary-side control unit proceeds to
step S309 or a subsequent step.
[0209] When it says that a positive result of decision is obtained
at step S307, it means that the deviation in a planar direction of
the position of the primary coil 12 from the position of the
secondary coil falls within the permissible range. At step S309,
the primary-side control unit 13 drives the indicator 18 so that
the fact that positioning has succeeded can be notified.
[0210] As long as a defined amount of current having a defined
frequency has already flowed for charging at step S306, step S310
may be skipped. For example, when the primary coil is driven with
an alternating current at step S306, if the defined amount of
current or the defined frequency has not been designated for
charging due to some restriction, the defined amount of current and
the defined frequency are designated for charging at step S310.
[0211] Although the standby time Tw2 has elapsed, if light
emanating from the light emitter 35 is not sensed, that is, if the
deviation of the position of the primary coil 12 from the position
of the secondary coil 22 exceeds the permissible range, the
primary-side control unit proceeds to step S311.
[0212] At step S311, similarly to step S110 shown in FIG. 4, a
decision is made on whether the number of times of repetition for
the processing of making the primary coil 12 movable at step S302
to step S308 and the subsequent processing of deciding whether
light is sensed has reached a defined number of times. As long as a
negative result of decision is obtained at step S311, the
primary-side control unit 13 proceeds to step S302.
[0213] In contrast, if a positive result of decision is obtained at
step S311 because the number of times of repetition has reached the
defined number of times, the primary-side control unit 13 proceeds
to step S312. At step S312, driving the primary coil 12 with an
alternating current is ceased. At step S313, similarly to step S111
in FIG. 4, the indicator 18 is driven in order to notify of the
fact that positioning has failed as an error. The primary-side
control unit then returns to step S302. Ceasing the driving with an
alternating current at step S312 is processing of making
preparations for driving of the primary coil with a direct current
at step S302 included in a subsequent loop. For example, step S311
may be skipped, and the driving with an alternating current may be
switched to the driving with a direct current at step S302.
[0214] In the equipment to be charged 2, the secondary-side control
unit 31 begins driving the light emitter 35 so as to allow the
light emitter 35 to emit light at step S404. At step S405, the
secondary-side control unit 31 ceases driving the secondary coil 22
with a direct current, and sets the secondary coil 22 to a charging
standby state.
[0215] What is referred to as the charging standby state is a state
of a mode to be described below.
[0216] Specifically, the secondary coil 22 is made conducting so
that once the secondary coil 22 and primary coil 12 are inductively
coupled to each other, the secondary coil 22 can receive a current,
that is, the secondary coil 22 can exert induced electromotive
force. When the induced electromagnetic force is exerted in the
secondary coil 22, an operating mode in which the secondary-side
control unit 31 feeds a charging current to the secondary battery
32 using the induced electromotive force so as to thus charge the
secondary battery 32 is designated. The foregoing conducting state
is equivalent to, for example, a state in which the secondary coil
22 is driven with an alternating current at step S205 shown in FIG.
4.
[0217] In the equipment to be charged 2, the secondary-side control
unit 31 sets the secondary coil 22 to the charging standby state at
step S405. Whether the secondary coil 22 has received power is
decided at step S406 until a decision is made at step S407 that the
standby time Tw1 has elapsed. If the secondary coil 22 has received
power, an alternating voltage and current corresponding to the
power are inputted to the secondary-side control unit 31. At step
S406, a decision is made by deciding whether an ac voltage is
inputted from the secondary coil 22.
[0218] In this case, the charger 1 does not notify the equipment to
be charged 2 of the fact that light has been received. However, as
long as the deviation of the position of the primary coil 12 from
the position of the secondary coil falls within the permissible
range, the sensor 19 in the charger 1 can receive light emanating
from the light emitter 35. A positive result of decision is
obtained at step S307, and the primary coil 12 is driven with an
alternating current for charging (S310). In the equipment to be
charged 2, since the charging standby state is established at step
S405, induced electromotive force is exerted in the secondary coil
22. A positive result of decision is obtained at step S406. In this
case, the equipment to be charged 2 is retained in the charging
standby state. The charging standby state is regarded as an
operating mode in which if the secondary coil 22 can receive power,
the secondary battery 32 can be charged. When the fact that the
secondary coil has received power is sensed based on the result of
decision obtained at step S406, charging the secondary battery 32
is begun properly.
[0219] In contrast, when the deviation of the position of the
primary coil 12 from the position of the secondary coil 22 exceeds
the permissible range, a necessary and sufficient degree of
magnetic coupling is not attained between the primary coil 12 and
secondary coil 22.
[0220] Even when the fact that the secondary coil has received
power is recognized at step S406 and the secondary-side control
unit stands by at step S407, a defined amount of induced
electromotive force that should be induced for charging is
unavailable. As a result, a negative result of decision is obtained
at step S406, and a positive result of decision is obtained at step
S407. In this case, the secondary-side control unit 31 cancels the
charging standby state at step S408, and returns to step S402.
[0221] At this time, in the charger 1, even when the standby time
Tw2 has elapsed at step S308, light is not sensed by the sensor 19
at step S307. The primary-side control unit therefore proceeds to
step S311, and returns to step S302 as long as the number of times
of repetition falls below the defined number of times.
[0222] The timing at which the primary-side control unit returns to
step S302 nearly coincides with the timing at which the
secondary-side control unit of the equipment to be charged 2
returns from step S408 to step S402. Namely, for the pieces of loop
processing to be performed by the charger 1 and equipment to be
charged 2 respectively, since the standby times Tw, Tw1, and Tw2
are designated, the processing times for the respective steps are
known or can be designated. Therefore, the timings at which the
charger 1 and equipment to be charged 2 begin the pieces of loop
processing shown in FIG. 9 can be squared with each other.
[0223] As mentioned above, in the third embodiment, the light
emitter is incorporated in the equipment to be charged 2, and the
sensor is incorporated in the charger 1. Therefore, communication
may not be performed in order to notify of the fact that light
emanating from the light emitter has been sensed. Nevertheless, the
operating timings of the charger 1 and equipment to be charged 2
can be nearly squared with each other, and proper positioning
control can be implemented.
[4-3 Algorithm (Second Example)]
[0224] The flowchart of FIG. 10 shows an example of a processing
procedure as the second example of an algorithm to be followed by
the charger 1 and equipment to be charged 2 in accordance with the
third embodiment. According to the first algorithm, the charger 1
does not notify the equipment to be charged 2 of the fact that the
sensor 19 has sensed light emanating from the light emitter 35. In
contrast, according to the second example, the fact that the light
has been sensed is notified by utilizing the magnetic coupling
between the primary coil 12 and secondary coil 22.
[0225] In FIG. 10, the pieces of processing to be performed in the
charger 1 at step S501 to step S505 are identical to those to be
performed at step S301 to step S305 in FIG. 9. However, the
processing to be performed at step S306 in order to begin driving
the primary coil 12 with an alternating current at a step preceding
a step at which positioning succeeds is not shown in FIG. 10. In
this example, similarly to the aforesaid first and second
embodiments, when positioning succeeds, driving the primary coil 12
with an alternating current is begun. In this case, conduction of a
current to the primary coil 12 is ceased at step S505, but
conduction thereof to the other regions including the control unit
is carried on. The primary-side control unit proceeds to the
processing of deciding during the standby time Tw2 whether light
has been sensed which is performed at step S506 and step S507. The
step S506 and step S507 correspond to the step S307 and step S308
in FIG. 9.
[0226] The pieces of processing to be performed in the equipment to
be charged 2 at step S601 to step S603 are identical to those to be
performed at step S401 to step S403 in FIG. 9. When the standby
time Tw elapses at step S603, the secondary-side control unit 31
sets the secondary coil 22 to a pulse receiving mode at step S604.
At step S605, similarly to step S405 in FIG. 9, the secondary-side
control unit 31 drives the light emitter 35 so as to allow the
light emitter 35 to emit light over a certain time.
[0227] What is referred to as the pulse receiving mode is a mode in
which: the secondary coil 12 is brought to a conducting state; a
pulse is induced by the secondary coil 22 responsively to
application of a pulse to the primary coil 12 of the charger 1 at
step S508; and the secondary-side control unit 31 detects the pulse
induced by the secondary coil 22.
[0228] If a decision is made through step S506 and step S507 that
light is not sensed in the charger 1 despite the elapse of the
standby time Tw, the primary-side control unit proceeds to step
S511. Step S511 is identical to step S311 in FIG. 9. As long as a
negative result of decision is obtained, the primary-side control
unit returns to step S502. If a positive result of decision is
obtained, the primary-side control unit performs counter-error
processing at step S512 similarly to step S313 in FIG. 9. In this
case, when conduction of a current to the primary coil 12 is ceased
at step S505, the conduction is kept ceased until positioning
succeeds. The processing corresponding to that of step S312 in FIG.
9 is omitted.
[0229] In contrast, if a decision is made that the sensor 19 has
sensed light until the standby time Tw elapses, that is, if the
deviation in a planar direction of the position of the primary coil
12 from the position of the secondary coil 22 falls within the
permissible range and power can be properly transmitted, the
primary-side control unit proceeds to step S508 or a subsequent
step.
[0230] At step S508, the primary-side control unit 13 applies a
single pulse or plural consecutive pulses to the primary coil 12.
Thereafter, similarly to step S309 and step S310 in FIG. 9, the
primary-side control unit 13 drives the indicator 18, which is used
to display the notification signifying that positioning has
succeeded, at step S509 and step S510, and drives the primary coil
12 with an alternating current for charging.
[0231] In the equipment to be charged 2, the secondary-side control
unit 31 designates the pulse receiving mode at step S604 and begins
driving the light emitter 35 so as to allow the light emitter 35 to
emit light at step S605. Thereafter, the secondary-side control
unit 31 stands by over the standby time Tw1 at step S607 until a
pulse induced by the secondary coil 22 is sensed at step S606.
[0232] Step S606 and step S607 are performed irrespective of
whether the charger 1 has sensed light emanating from the light
emitter 35. However, as long as the deviation of the position of
the primary coil 12 from the position of the secondary coil 22
falls within the permissible range, the charger 1 applies a pulse
to the primary coil 12 at step S508. Therefore, a pulsating voltage
is induced by the secondary coil 22, and a positive result of
decision is obtained at step S606. In this case, the secondary-side
control unit 31 of the equipment to be charged 2 establishes the
charging standby state at step S608. At this time, since the
charger 1 has begun driving the primary coil 12 with an alternating
current for charging at step S510, induced electromotive force is
exerted in the secondary coil 22. Thereafter, the secondary battery
32 can be charged.
[0233] In contrast, when the deviation of the position of the
primary coil 12 from the position of the secondary coil 22 exceeds
the permissible range, the primary-side control unit included in
the charger 1 proceeds from step S507 to step S511. No pulse is
therefore applied to the primary coil 12. Eventually, no pulse is
detected during the standby time Tw1 in the equipment to be charged
2, and the secondary-side control unit returns from step S607 to
step S602.
[0234] As mentioned above, according to the algorithm of the second
example employed in the third embodiment, a pulse is transferred
between the primary coil 11 and second coil 22 for the purpose of
notification. The communication means employed in the first and
second embodiments is replaced with transfer of the pulse.
Therefore, according to the algorithm of the second example, the
operating timings of the charger 1 and equipment to be charged 2
can be nearly squared with each other without the necessity of the
communication means. Proper positioning control is implemented.
[0235] In the embodiments shown in FIG. 1, FIG. 2, and FIG. 5, the
light emitter 15 is laid on the primary coil 12 on the substrate
11, and the sensor 23 is laid on the secondary coil 22 on the
substrate 21. However, as long as the positional relationship of
the light emitter 15 to the movable primary coil 12 remains
unchanged, the light emitter 15 may be disposed at a position in a
planar direction at which the light emitter 15 does not come into
contact with the primary coil 12. Accordingly, the sensor 23 may be
disposed at a position at which the sensor 23 does not come into
contact with the secondary coil 22.
[0236] The primary coil moving mechanism is not limited to the
structures employed in the first and second embodiment
respectively.
[0237] The primary-side receiving unit 16 and secondary-side
notification unit 33 may be, for example, hardware devices
independent of the light emitter 15 or sensor 23. Otherwise, a
device having the capabilities of the light emitter 15 and
primary-side receiving unit 16 may be adopted, and a device having
the capabilities of the sensor 23 and secondary-side notification
unit 33 may be adopted.
[0238] Unlike the embodiments, a constitution in which a coil
moving mechanism is incorporated in equipment to be charged, and a
coil is incorporated in a charger is conceivable. However, when a
coil is movable in the charger, it is advantageous because a wider
movable range can be preserved, and also advantageous in terms of
versatility and universality. Since the equipment to be charged is
often of a portable type, incorporation of a movable element in an
internal circuit should be avoided from the viewpoint of, for
example, durability.
[0239] As described previously, the constitutions for positioning
control in accordance with the embodiments of the present invention
are not especially limited to any specific equipment to be charged.
The constitutions are effectively applied to pieces of electronic
equipment including a device, which has a permanent magnet, therein
or pieces of electronic equipment having a magnetic recording
medium incorporated therein.
[0240] In this case, non-contact charging has been taken for
instance. The embodiments are not limited to charging but may be
applied to a system in which power is fed wirelessly or electronic
equipment to which power is fed.
[0241] In addition, the embodiments can be applied to any
electronic equipment other than typical electronic equipment that
is regarded as power-receiving equipment. For example, the
embodiments can be applied to non-contact charging to be performed
on a secondary battery mounted in an automobile, for example, an
electric automobile or a hybrid automobile. In this case, a
charging facility includes a primary coil disposed on the ground or
the like. An automobile is driven or moved to a place where the
primary coil is installed, and then halted. With the automobile
halted, induced electromotive force is exerted between the primary
coil and a secondary coil mounted in the automobile in order to
charge the secondary battery.
[0242] When the charging facility (power feeder) is utilized, it is
very hard to accurately halt the automobile (power-receiving
equipment) at a position in a charging place at which power is
efficiently transmitted. When the constitution of any of the
embodiments is adopted, even when the automobile is not halted at
the exact position, power is optimally transmitted. Even when the
automobile is stopped, since a driver may not be concerned about
positioning, the user will find the constitution easy to use.
[0243] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalents thereof.
* * * * *